输出  2

#include <iostream>
#include<algorithm>using namespace std;const int N =100010 ;int n;
struct Range
{int l,r;bool operator <(const  Range &W)const{return r<W.r;}
}range[N];int main()
{scanf("%d",&n);for(int i=0;i<n;i++){int l,r;scanf("%d%d",&l,&r);range[i]={l,r};}sort(range,range+n);int res=0, ed=-2e9;for (int i=0;i<n;i++)if(range[i].l>ed){res++;ed=range[i].r;}printf("%d\n",res);return 0;
}

ed 上一个点的下标